Plant Interactions with the Environment

Plant Evolution: How have plants adapted over time to survive in different environments?

Bryophytes: Mosses Have cuticle & stomata, but no true roots Water is required for fertilization Fertilization occurs with spores

Non- Seed Plants: Produce spores Can be vascular or non-vascular, but have no true roots All vascular have xylem and phloem Whisk ferns, horse tails, club and ferns are vascular non-seeded Horse Tails Ferns

Seed Plants Gymnosperms and Angiosperms produce seeds more effective than spores cones, flowers, pollen and seeds are adaptations that allow fertilization without water all are vascular Use xylem and Phloem

Rely on wind for pollination Gymnosperms Angiosperms Use pollen and cones “naked seed” plants Rely on wind for pollination Examples include pines, firs, spruces, junipers, cedars, cypress, and redwoods. Use pollen and flowers These seeds develop inside a fruit Angiosperms are most successful because of the fruits and flowers (Evolution)

Everyday Plant Adaptations Phototropism – Plants move towards the sunlight for more energy Gravitropism – Plants grow towards gravity for water Selective Stomata Opening and Closing – Plants Conserve Water

Biome Adaptations: Rainforest Slide shaped leaves allow water to run off to prevent fungal infections Stilt root systems allow for better anchorage in shallow soil Large leaf size help plants trap sunlight so photosynthesis can occur with little available sunlight

Biome Adaptations: Tundra Grow close to the ground for warmth Shallow root systems to absorb limited available water Dark pigmented plants absorb more heat

Biome Adaptations: Desert Deep roots to access water stored underground Few stomates to prevent water loss Thick cuticle to prevent water loss

Plant Responses Tropisms- response to external stimuli may be positive (toward the stimuli) negative (away from the stimuli) respond to hormones that cause growth, fruiting, cell division, and ripening

Types of Tropisms: Gravitropism- response to gravity (stems and roots); (negative and positive) Phototropism- positive, plants grow toward light Thigmotropism- response to pressure (Venus flytrap) Nastic Movement- touch; vines attach to wall Ex - Venus Flytrap (decrease in turgor pressure)

Hormones in Plants Auxin Cytokinins Gibberellins Abscisic Acid Stimulates stem growth Causes plant to grow toward the light Cytokinins Affects root growth, stimulates cell division Gibberellins Promotes seed and bud germination Abscisic Acid Inhibits growth, closes stomata, seed dormancy Ethylene Promotes fruit ripening Ripening will slow down in lower temperatures